It is essential that when going through a parentage action or divorce, that you account for holiday custody arrangements to avoid problems down the line.
Typically people will alternate who has Thanksgiving and Christmas (for example mom gets Thanksgiving on even years (2012, 2014 etc) and Dad gets Thanksgiving on odd years (2013, 2015, etc). The same is done with Christmas, except the parent who gets Thanksgiving is usually not the person who gets Christmas that year. Parents often also give Christmas Eve to the person who does not have the child on Christmas days.
Of course there are different schedules for each family. If you live far apart, cultural/religious schedules, etc are all important factors that play a part on the schedule that your family will agree to.
No matter what schedule works for you, make sure it is part of your court order so that there is no confusion and so it can be enforced later.